The existence of a world with a double sunset, as portrayed in the film Star Wars more than 30 years ago, is now scientific fact. NASA’s Kepler mission has made the first unambiguous detection of a circumbinary planet — a planet orbiting two stars — 200 light-years from Earth.

Unlike Star Wars’ Tatooine, the planet is cold, gaseous and not thought to harbor life, but its discovery demonstrates the diversity of planets in our galaxy. Previous research has hinted at the existence of circumbinary planets, but clear confirmation proved elusive. Kepler detected such a planet, known as Kepler-16b, by observing transits, where the brightness of a parent star dims from the planet crossing in front of it. “This discovery confirms a new class of planetary systems that could harbor life,” Kepler principal investigator William Borucki said. “Given that most stars in our galaxy are part of a binary system, this means the opportunities for life are much broader than if planets form only around single stars. This milestone discovery confirms a theory that scientists have had for decades but could not prove until now.”

Both of the suns are smaller and cooler than our system’s sun. Kepler-16b is a gassy giant, approximately the size of Saturn and equally as uninhabitable. Think Hoth on a bad day.

Doyle* said Kepler-16b almost certainly will not be the last double-sunset planet discovered by the $600 million Kepler mission. When the numbers all added up, “I didn’t feel like it’s the end of 20 years of searching … it felt like the beginning of something” he said. “I predict that in the next couple of months, we’re going to have some more.”

But time’s running out for Kepler. Boss** noted that the current mission plan calls for the telescope to be “out of business one year from now.” That would be a shame, Boss said, because it looks as if it will take longer than expected for Kepler to get the data to identify Earthlike planets in Earthlike orbits around sunlike stars – which is the mission’s prime objective. The reason for that is that the readings from alien suns are unusually noisy. “It turns out that most stars are not as quiet as the sun,” Boss said. (Signs of the Times/Science & Technology)

* Laurance Doyle of the SETI Institute in Mountain View, California, who served as discovery team leader and paper lead author
** Carnegie Institution astronomer Alan Boss, a member of the team for NASA’s Kepler mission and paper co-author

Kepler concentrates on searching for Earth-like, inhabitable planets in the constellations Cygnus and Lyra. To date, 21 planets matching the mission criteria have been found. Years of hard work and research have culminated in a fascinating discovery. Alas, these dark days everything falls prey to budget cutsImperial entanglements.

The full research paper paper was published Thursday in Science (subscription required).